Health Directory - A theme is defined by search engines as a common topic throughout the site. In an effort to provide their users with more relevant information, search engines developed sophisticated technology that "extracts" site's themes. This technology allows results to be more focused on the topic searched for. Hint: Think of themes as your most important keywords. Themes technology is quite complex. Factors analyzed are: HTML title, meta tags, headings, text on the site, and links. Spiders use technologies such as keyword weighting, extrapolation and root stemming to determine a theme. Excite, Altavista, Lycos and Google use them Inktomi should be joining soon Determined by keywords in title, meta tags, text and links.